1. Field of the Invention
The present invention relates to a device for securing articles together. In particular, the present invention relates to a device for securing together mats used as structural supports for roadways and the like.
2. Description of the Related Art
Many fastening devices for joining various elements are known in the art. A few examples of such devices are U.S. Pat. Nos. 5,779,422; 4,801,232; 4,498,827; and 2,811,765. Other fastening devices have specific applications. For example, U.S. Pat. No. 5,632,586 discloses an automatic twist lock primarily used with shipping containers, and U.S. Pat. No. 5,346,349 discloses a fastening device for assembly of components of pieces of furniture or furnishings in general.
A smaller number of such devices are used to interconnect and secure flat shaped components. For example, U.S. Pat. No. 4,604,962 discloses an interlocking assembly for modular loading dock units.
Rigid large sized industrial mats are used as structural supports. Multiple mats can be placed adjacent to each other and connected together to provide support for roadways and other structures. When adjacent mats are secured together, the collection of secured mats function as one large mat rather than a collection of individual mats. Any successful fastening device must provide substantial holding strength to secure the mats and prevent separation. Particularly, when mats are used in roadway surfaces, extreme pressures are placed on the adjoining mats and the locking mechanism.
Some devices in use to secure the mats include fasteners with carriage bolts that restrict lateral movement of the mats but do not successfully restrict vertical movement. With movement of the mats relative to each other, the carriage bolts often work their way out, presenting a hazard to personnel and vehicles using the mats.
Other fastening devices use a keeper drawn up by a screw; however, harsh conditions and contaminants such as mud, sand and/or debris can impair the operation of any threaded device or devices that allow contaminants to enter and impair their working mechanisms. The present invention does not utilize threaded elements and is better adapted to operate in harsh conditions.
The present invention provides a fastening device for fastening and securing adjacent panels or mats together by placement of the fastening device in slots in overlapping lips of adjacent mats and includes a keeper which is rotated under the bottom of adjacent mats to prevent removal of the fastening device.
The fastening device includes a rigid pin with an enlarged head, and a central bore. The pin is shaped to fit aligned slots or holes of adjacent mats, and the pin is generally of an oblong shape to resist rotation in the aligned holes. The depth of the pin is designed to match the depth of two overlapping mats.
The enlarged head of the pin prevents the pin from dropping through the mat hole and ideally is engineered and designed to allow the pin to drop to a level to be flush with the top of the mat when locked into place. The enlarged head of the pin has a top opening to the central bore which can also receive a protective cap.
The central bore of the pin receives a footed rod having an enlarged head with a drive receiving recess which can be protected by placing a protective cap in the top opening of the central bore of the pin. The footed end of the rod has a keeper aligned generally perpendicular to the rod and placed below and outside of the pin body. In its preferred embodiment, the keeper has a tapered or helical surface that allows easier rotation of the keeper during its initial contact with the bottom of the mat. The tapered feature provides some compression of the mats as the thickest portion of the keeper fully contacts the bottom of the mat.
In use, the pin, with its keeper in the unlocked position such that the keeper does not extend outside the longitudinal projected body of the pin, is inserted into aligned openings of the mated articles. A torque-applying tool is then inserted in the drive receiving recess to turn the rod and the keeper resulting in the keeper extending into the longitudinal projected volume of the bottom mat to prevent pin removal. The wall of the pin bore and midbody of the rod have interacting surfaces which aid in the prevention of free tuning relative to each other.